This language feature is only available from Ada 2005 on.
The Package DirectoriesEdit
Used for simple directory manipulation as defined in Ada 2005.
Changing the current working directory is done with
Set_Directory. The remaining functions are fairly self-explanatory with the exception of
Containing_Directory, which returns the name of the directory containing the given directory.
function Current_Directory return String; procedure Set_Directory (Directory : in String); function Exists (Name : in String) return Boolean; function Containing_Directory (Name : in String) return String;
Enumerating Directory EntriesEdit
This example enumerates the all the entries in the current working directory, that end in ".gpr". The
Start_Search procedure is used to start enumerating a directory. It will To remove the filter criteria you can pass an empty string. Iterating through the directory involves calling
Get_Next_Entry to return the next directory entry and
More_Entries to check for more entries. Once the search is complete, call
type Search_Type is limited private; type Directory_Entry_Type is limited private; procedure Start_Search (Search : in out Search_Type; Directory : in String; Pattern : in String; Filter : in Filter_Type := (others => True)); procedure Get_Next_Entry (Search : in out Search_Type; Directory_Entry : out Directory_Entry_Type); function More_Entries (Search : in Search_Type) return Boolean; procedure End_Search (Search : in out Search_Type);
The resulting Directory_Entry_Type has a full name, simple name, size, kind, and modification type.
function Simple_Name (Directory_Entry : in Directory_Entry_Type) return String; function Full_Name (Directory_Entry : in Directory_Entry_Type) return String; function Kind (Directory_Entry : in Directory_Entry_Type) return File_Kind; -- Directory, Ordinary_File, Special_File function Size (Directory_Entry : in Directory_Entry_Type) return File_Size; function Modification_Time (Directory_Entry : in Directory_Entry_Type) return Ada.Calendar.Time;
with Ada.Text_IO; with Ada.Directories; use Ada.Text_IO; use Ada.Directories; procedure Main is Dir : Directory_Entry_Type; Dir_Search : Search_Type; Curr_Dir : string := Current_Directory; begin Put("Current Directory: "); Put_Line(Curr_Dir); Start_Search(Search => Dir_Search, Directory => Curr_Dir, Pattern => "*.gpr"); loop Get_Next_Entry(Dir_Search, Dir); Put(Full_Name(Dir)); Set_Col(50); if Kind(Dir) = Ordinary_File then Put(Size(Dir)'Image); end if; Set_Col(60); Put_Line(Kind(Dir)'Image); exit when not More_Entries(Dir_Search); end loop; End_Search(Dir_Search); end Main;
Creating a directory is done with
Create_Path creates all the directories in the path. The directory path on GNAT Ada can contain either "\" or "/" characters.
Rename renames a directory or file within a directory. <Delete_Tree> deletes an entire hierarchy of directories and files.
Delete_Directory deletes an empty directory (non-empty directories throw a
Delete_File deletes an ordinary file in a directory. Note that the
Form parameters is implementation specific. On the version of GNAT Ada I'm using, it can only be used to set the encoding.
procedure Create_Directory (New_Directory : in String; Form : in String := ""); procedure Create_Path (New_Directory : in String; Form : in String := ""); procedure Rename (Old_Name, New_Name : in String); procedure Delete_Tree (Directory : in String); procedure Delete_Directory (Directory : in String); procedure Delete_File (Name : in String);
Below is a simple example that creates a set of directories and iterates through those directories. Note that it runs on both Windows and Linux with the "/" path separator. The returned path separators are appropriate to the filesystem (e.g. Windows return "\").
procedure Main is Dir : Directory_Entry_Type; Dir_Search : Search_Type; begin Start_Search(Search => Dir_Search, Directory => Curr_Dir, Pattern => ""); Create_Path("Foo"); Create_Path("Bar/Baz/Qux"); loop Get_Next_Entry(Dir_Search, Dir); Put_Line(Full_Name(Dir)); exit when not More_Entries(Dir_Search); end loop; End_Search(Dir_Search); Delete_Directory("Foo"); Delete_Tree("Bar"); end Main;
Status_Error is raised if a directory entry is invalid or when enumerating directories past the last directory.
Name_Error is usually thrown if the directory or filename is not able to identify a file or directory (either non-existent or invalid depending on context).
Use_Error is thrown if directories are not support or directories are not traversable.
Status_Error : exception renames Ada.IO_Exceptions.Status_Error; Name_Error : exception renames Ada.IO_Exceptions.Name_Error; Use_Error : exception renames Ada.IO_Exceptions.Use_Error; Device_Error : exception renames Ada.IO_Exceptions.Device_Error;
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